Article attaching machine



vApril 4,1944.

M. MCCANN 'ARTICLE ATTACHING MACHINE ,Filed sept. 5, 1942 sa l' Patented Apr. 4, i944 ARTICLE ATTACHING MACHINE Michael McCann, Elizabeth, N. J., assigner to The Singer Manufacturing Company, Eliza.- beth, N. J., a corporation of New Jersey Application September 3, 1942, Serial No. 457,131

Claims.

This invention relates to sewing machines of the type used for performing tacking and articleattaching operations and it is directed more particularly to improved means for nipping the beginning end of the thread, to insure formation of the initial stitch of a stitch-forming cycle, and for subsequently trimming 01T the beginning end of the thread adjacent the work.

The invention has as its primary object to provide an improved thread-nipping and -severing mechanism in which one of two relatively movable thread-severing blades is adjustable relative to the other to compensate for irregularities and inaccuracies in manufacture and/or subsequent slight deformations of either blade, thereby to obtain and maintain complete contact between the opposed cutting edges. This insures that all thread fibers will be severed and that the thread-end will be completely detached' from the work.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth andV illustrated in the accompanying drawing of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

For convenience, this invention is shown and described in connection with a button-sewing machine but it is to be understood that it is equally adaptable to other types of article-attaching and tacking machines.

In the drawing,

Fig. 1 is a side elevation of a button-sewing machine embodying the present invention.

Fig. 2 is an enlarged right end view of the work-supporting bed of thefmachine illustrated in Fig. 1.

Fig. 3 is a horizontal section taken substantially on the line 3-3 of Fig. 2 showing, in plan view, the thread-nipping and -severing mechanism, later to be described.

Fig. 4 is an enlarged longitudinal sectional view taken substantially on the line 4-4 of Fig. 2 showing the needle in itsvflrst upward movement after the beginning of a stitch-forming cycle and with the looper drawing down the beginning end of the thread.

Fig. 5 is a view similar to Fig. 4 but showing an element of the thread-cutting mechanism shifted to a position in which it nips the beginning end of the thread.

Fig. 6 is a view similar to Fig. 5 but showing the movable element of the thread-cutting mechanism shifted to a position in which it trims off the beginning end of the thread.

Referring more specifically to the drawing, the invention is disclosed as embodied in a buttonsewing machine comprising a base I affording a horizontally disposed work-supporting arm 2, standard 3, overhanging bracket-arm 4 and a bracket-arm head 5. Journaled within the arm 4 is a main shaft 6 carrying loose and fast pulleys 1 and 8, respectively, adapted to be driven by a power belt, not shown. A combined stopmotion mechanism and belt-shifter, designated generally as 9, is swung in one direction by a treadle-actuated chain I0 and lever I I to shift the belt from the loose pulley 'I to the fast pulley 8 to start the operation of the machine. At the end of the stitching cycle the stop-motion is tripped automatically and swung in the opposite direction whereupon it shifts the belt to the loose pulley and brings the machine to rest with the parts in a predetermined position. Inasmuch as this stop-motion mechanism forms no part of the present invention, detailed illustration-and description thereof is deemed unnecessary.

Rotatably journaled in bearings provided by the base I and driven from the main shaft 6 by twcsets of bevel gears a and b and a vertically disposed shaft c is a looper shaft I2, which carries, at its forward end, a rotary chain-stitch looper I3. Cooperating With the looper in the formation of stitches is an eye-pointed needle I4 secured in the lower end of a needle-bar I5 mounted for endwise reciprocation in the head 5. The needle-bar is reciprocated from the rotary main shaft 6 through the medium of a conventional crank-and-link mechanism designated generally as I6.

A throat-plate I'I is secured upon the upper face of the work-supporting arm 2 and is provided with a needle-hole I3 through which the pointed end of the needle passes for cooperation with the looper.

Movably mounted on the upper surface of the work-supporting arm is a Work-holder H comprising a Work-supporting plate I9, having a needle aperture I9a in vertical alignment with the needle-hole I8, and an overlying spring-depressed button-clamp 2U having jaws 2I which are normally pressed downwardly upon the work w on the plate I9 and hold a button B to be attached to the work (see Fig. 4). This workclamp is adapted to be vibrated laterally of the arm 2 by mechanism similarV to that disclosed in U. S. patent to Horton, No. 807,676, Dec. 19, 1905. Stated briefly, this mechanism includes a camwheel 22 secured upon a shaft 23 journaled in the standard 3 and rotated from the main shaft 6 by a worm 24 and worm-wheel 25. The wheel 22 is provided with a cam groove 22a which is tracked by a roller 25a carried by the upper arm of a two-armed lever 26 journaled, at 2l, in a bracket 28 secured upon the arm 2. The lower arm of the lever 25 is connected to the workclamp, to give vibratory movements thereto, through the medium of a rst link 29, bell-crank lever 3l! and a second link 3|, as disclosed more fully in said Horton patent.

Ii it is desired to attach four-hole buttons the work-clamp may also be shifted endwise after the machine has completed one-half the stitching cycle, thereby to align the second pair of holes in the button with the needle. The mechanism for giving this movement to the work-clamp is of conventional form and forms no part of this invention. Detailed illustration and description thereof is, therefore, deemed unnecessary.

Slidingly mounted in the head is a clamplifting bar 32, carrying, at its lower end, an arm 33 which engages beneath an upstanding hook 34 carried by the spring-depressed work-clamp to lift the clamp in opposition to its depressing spring 35.

The machine also includes means actuated at the completion of a sewing cycle for automatically lifting the Work-clamp, thereby to break the thread and release the Work and for lowering the clamp onto the work at the beginning of a succeeding cycle. This automatic clamp-actuating means forms the subject of my pending United States patent application Serial No. 365,045 led Nov. 9, 1940, and includes a push rod 38 slidable lengthwise of the arm 4. A coil spring 40, in-

terposed between an abutment provided by the head 5 and a collar 4| on the rod, normally acts to urge the rod 38 toward the cam-wheel 22 and a cam 43 secured upon the periphery of said cam- Wheel acts, near the completion of the stitching cycle, to shift the rod in the opposite direction in opposition to said spring. Within the head 5 the rod actuates means for causing the needlebar periodically to be connected to and disconnected from the clamp-lifting bar 32, all as shown and described in detail in my above mentioned application.

The means for nipping the thread at the beginning of a stitch-forming cycle to insure formation of the first stitch and for subsequently trimming off the beginning end of the thread close to the under side of the work comprises a movable blade 44 slidingly mounted in a channel 45 formed in the under side of the throat-plate Adjacent its rear end, the blade 44 carries an upstanding stud 46 which projects through a slot 4l in the throat-plate and is connected to the forward end of a horizontally disposed and endWise movable bar 48. At its rear end the bar is connected to an extension block 4S which is pivotally connected, at 50, to the lower arm `5| of a bell-crank lever 52 fulcrumed, at 53, on a bracket 54 secured upon the arm of the machine. The other arm 55 of the lever 52 carries a stud 56 which tracks a cam-groove 5l formed in the cam-wheel 22. The major portion of the camgroove 5'! is concentric with the axis of the camwheel 22 but a minor portion thereof is stepped, as later will be described, to eect, during rotation (f the wheel, oscillatory motions of the lever 52 and thereby -endwise movements of the bar 48 and cutter-blade 44. At its forward end the blade 44 is formed with an off-set portion 44IL provided with an aperture 58 which, during the rst down stroke of the needle, is aligned with the needle-hole |8 in the throat-plate, as shown in Fig. 4. One wall of the aperture 58 is formed with a rounded upper portion 59 adapted to nip the thread against the under side of the throatplate as later will be described, and a sharp lower corner 60 which constitutes a thread-cutting edge to trim off the beginning end of the thread.

Cooperating with the cutting edge 50 of the movable blade 44 in trimming off the beginning end of the thread is a normally stationary blade 6| having a cutting edge 62 normally maintained in pressure contact with the under side of the blade 44.

In practice, the blades 44 and 6| are made of relatively thin metal and heretofore great difllculty has been experienced in obtaining and maintaining a true surface contact between the blades and a line contact between the cutting edges thereof. Prior to this invention should either of the blades be not accurately made or assembled or should either of them subsequently become slightly bent, tiltedor otherwise deformed one blade might assume a slight angle to the other in the direction of the length of the cutting edge, with the result that the blades would be in pressure contact at one portion of the cutting edge and slightly spaced apart at another portion of the cutting edge. When this condition obtains not all of the thread fibers will be severed and therefore the thread end will remain attached to and dangling from the under side of the work.

To overcome this objectionable condition I have so mounted the normally stationary blade that it is permitted to float in its holder and thereby adapt itself to any angular position which the movable blade may assume. This has been attained by supporting the stationary blade 6| in a channel 63 formed in a bracket 64 secured to the under side of the throat-plate The channel is suliiciently large to permit the blade 6| to have universal movement therein but the blade is prevented from having any substantial bodily movement in the channel by having a stud 65 carried by the bladelocated within a bore 66 in the bracket transverse to the channel 63. At its upper face the blade 6| is provided with a semi-spherical projection 61 adapted to bear against the under side of the throat-plate. This projection and its contact with the throatplate afford a universal pivot about which the blade 6| may turn to adapt itself to any angular position of the blade 44. The semi-spherical projection conveniently may be provided by the upper projecting end of the stud 65. An adjusting screw 68, having a rounded upper end, is threaded through the bracket 64 and Vengages the blade 6| on its longitudinal center line thereby to tip the blade upwardly to cause its-cutting edge 62 to bear against the under side of the oiset portion 44B of the blade 44. vA Vlock-nut 69' on the screw 68 engagesy the under side of the bracket 64fand holds the screw .against accidental displacement. Inasmuch as the .rounded end of the screw bears on the center line of the blade 6| in line with the universal pivot 61 it does not interfere with the free tilting of the blade along that center line. The blade therefore is permitted to conform to any angular position assumed by the blade 44 whereupon-complete line contact is eiected and maintained between the cutting edges BIJ and 62 thereby insuring that the thread end will be severed completely. The blade 6| is preferably maintained at a slight inclination relative to the blade 44, as shown in Figs. 4, and 6. This assists in bringing the cutting edges into close line contact with each other and also tends to make the blades self-sharpening. v

Continued operation of the thread-cutter, however, will eventually cause the cutting edge 62 of the blade 6I to become dulled and it will therefore require resharpening, To compensate for wear in that blade due to use and resharpening, provision is made for adjusting the blade 6I endwise toward the cutting edge 62 of the blade 44. To that end, the bracket 64 in which the blade is supported is preferably pivotally mounted at one end on the throat-plate, as by pivot screw 1U. At its opposite end the bracket is formed with a slot 1| and a screw 12 passing therethrough and threaded intothe throat-plate permits the bracket to be adjusted about the pivot screw 10 and clamped in its adjusted position.

Operation y The operation of this improved thread-end nipper and cutter is as follows:

At the completion of a stitching cycle the machine comes to rest with the parts in the positions shown in Fig. 1 and with the cutter-'blade 44 inthe position shown in Fig. 5, but without the thread-end nipped thereby. During the rst quarter rotation of the main shaft in a succeeding operation the needle-bar is partially lowered, thereby lowering the clamp onto the work. At the same time the cam-wheel 22 is partially rotated in the direction indicated by the arrow thereon thereby causing the roller stud 55 to ride outwardly into the outer portion 45la of the cam groove 51. This causes the bell-crank lever 52 to be turned clockwise, as seen in Fig. l whereupon the lower arm 5| of the lever draws the bar 48 toward the standard 3 thereby shifting the cutter blade 44 to its rearmost position shown in Fig. 4, with the aperture 58 therein aligned with the needle-hole I8 in the throatplate. Further rotation of the main shaft causes the needle to descend through the button B, the work w, the needle hole I8 and aperture 58 and then to be retracted, whereupon it throws out a loop of the needle-thread t, which loop is seized by the looper I3. Rotation of the looper draws the thread-end down below the throat-plate as shown in Fig. 4. As the needle rises after its rst down stroke rotation of the earn-wheel 22 causes the stud 56 to ride down the incline 51b of the cam groove 51 thus swinging the lever 52 counter-clockwise and shifting the blade 44 to the position shown in Fig. 5 in which the portion 59 thereof nips the thread between the blade 44 and the under side of the throat-plate. The lever 52 and the blade 44 remain in this position while the sewing machine continues to operate and the stud '56 tracks the concentric major portion of the cam groove 51. As the needle descends in its second last stroke the stud 56 rides down the incline 51c into the portion 51d of the cam groove. This causes the lever 52 to be given a further counter-clockwise movement whereupon the blade 44 is moved from the thread-nipping position shown in Fig. 5 to the thread-trimming position shown in Fig. 6,

edges 60 and B2 close to the under side of the throat-plate. Inasmuch as the cutting edgesof the two thread-severing blades are maintained in complete line contact throughout their length all of the thread iibers will be severed and the beginning end portion t of the thread will be wholly detached from the work. During the final reciprocation of the needle the stud 56 moves outwardly into the portion 51e of'the cam groove 51 thereby swinging the lever 52 clockwise and retracting the blade 44 from the position shown in Fig. 6 to the position shown in Fig. 5. The machine is brought to rest by the stop-motion with the blade 44 in this position and with the looper holding the last thread-loop. The final upward movement of the needle-bar lifts the work-clamp and breaks the thread close to the under side of the work.

Having thus set forth the nature of the invention what I claim herein is:

1. In a sewing machine having an endwise reciprocatory thread-carrying needle, a looptaker cooperating with said needle in the formation of stitches and a pair of relatively movable thread-severing blades having opposed and contacting cutting edges for trimming off the beginning end of the sewing thread; the improvement which consists in the provision of means acting on opposite faces of one of said blades for adjusting it about an axis substantially perpendiular to the cutting edge of said blade to effect line contact between said blades along said cutting edges.

2. In a sewing machine having an endwise reciprocatory thread-carrying needle, a looptaker cooperating with said needle in the formation of stitches and a pair of relatively movable thread-severing blades having overlapping ends affording opposed cutting edges for trimming off the beginning end of the sewing thread; the improvement which consists in the provision of a .universal pivot for one of said blades and manually actuable means acting on said one of said blades, remote from said pivot, for adjusting it bodily toward the other blade and for tilting the adjusted blade about its universal pivot to effect line contact between said blades along said cutting edges.

3. In a sewing machine having a throat-plate, an endwise reciprocatory thread-carrying needle, a loop-taker cooperating with said needle in the formation of stitches and a pair of relatively movable and substantially parallel thread-severing blades located beneath said throat-plate and having opposed and contacting cutting edges for trimming off the beginning end of the sewing thread; the improvement which consists in the provision of a universal pivotal connection between one of said thread-severing blades and said throat-plate, means for adjusting said one of said blades angularly about an axis intersecting said pivotal connection and the cutting edge of said blade to effect line contact between said blades along said cutting edges, and means for shifting said one of the blades bodily along said axis toward the other blade to compensate for wear in said blades.

4. In a sewing machine having an endwise reciprocatory thread-carrying needle, a looptaker cooperating with said needle in the formation of stitches and a pair of horizontally disposed thread-severing blades of which one is movable and the other is normally stationary, said blades having opposed cutting edges for trimming oi the beginning end of the sewing thread; the improvement which consists in the provision of a universal pivot for the normally stationary blade, and manually actuable means for adjusting the normally stationary blade about its pivotV toward the movable blade and about an axis substantially perpendicular to the cutting edge thereof to bring said blades together and to eiTect line contact between said blades along said cutting edges.

5. In a sewing machine having an endwise reciprocatory thread-carrying needle, a looptaker cooperating with said needle in the formation of stitches and a pair of horizontally disposed thread-severing blades of which one is movable and the other is normally stationary, said blades having opposed cutting edges for trimming off the beginning end of the sewing thread; the improvement which consists in the provision of a bracket provided with a channel receiving said normally stationary blade for floating movement therein, means to retain said blade in said channel, and manually aotuable means for adjusting the normally stationary blade toward the movable blade to bring said blades together and to effect line contact between said blades along said cutting edges.

6. A sewing machine comprising stitch-forming mechanism, a throat-plate, thread-severing means located beneath said throat-plate and including a normally stationary blade and a cooperating movable blade, said blades having opposed cutting edges, a bracket secured to the under side of said throat-plate and having a channel receiving said normally stationary blade 3 for oating movement therein, means to Vmaintain said blade in said channel, and manually adjustable means for shifting said normally stationary blade toward said movable blade and for tilting it to cause it to conform tov any angular position of the movable blade, thereby to effect line contact between said blades along said cutting edges.

'7. A sewing machine comprising stitch-forming mechanism, a throat-plate, thread-severing means located beneath said throat-plate and including a normally stationary blade and acooperating movable blade, said blades having opposed cutting edges, a bracket secured to the under side of said throat-plate and having therein a channel and a bore transverse to said channel, said channel receiving said normally stationary blade for floating movement therein, a stud on said stationary blade projecting into said bore to prevent substantial bodily displacement of the blade, a semi-spherical pivotal connection between one side of said stationary bladev and said throat-plate to permitv universal adjustment of the blade, and a screw threaded through said bracket and engaging the opposite side of said stationary blade for shifting the normally stationary blade toward said movable blade and for tilting it on its pivot to cause it to conform to any angular position of the movable blade thereby to effect line contact between said blades along said cutting edges.

8. A thread-cutting mechanism. for a sewing machine having a throat-plate, comprising a pair of relatively movable substantially parallel blades having opposed thread-cutting edges, means for relatively moving said blades in a plane substantially parallel to the plane of the blades to sever the thread, a universal pivotal connection between one face of one of said blades and said throat-plate, and adjusting means acting on said one of said blades remote from its universal pivot and on the opposite face thereof to cause it to conform to any angular position of the other blade thereby to maintain said blades in line contact with each other along said cutting edges.

9. A thread-cutting mechanism for sewing machines comprising a movable blade and a cooperating normally stationary blade, said blades having opposed thread-cutting edges, means for moving said movable blade to sever the thread, and means including a universal pivot for the normally stationary blade and an adjusting screw acting on said normally stationary blade to adjust the blade about its pivot to cause the normally stationary blade to conform to any angular position of the movable blade, thereby to maintain said blades in line contact with each other along said cutting edges.

10. A thread-cutting mechanism for sewing machines comprising a movable blade and a cooperating normally stationary blade, said blades being arranged substantially parallel to each other and having opposed thread-cutting edges, means for moving said movable blade to sever the thread, means acting on opposite faces of said normally stationary blade to cause it to conform to any angular position of the movable blade, thereby to maintain said blades in line contact with each other along said cutting edges, l

and means for adjusting one of said blades edge- Wise toward the other blade to compensate for wear in said blades at said thread-cutting edges.

MICHAEL MCCANN. 

